Present day telephony voice networks, have a network built around circuit switches, end offices, a toll network, tandem switches, and twisted pair wires. These voice networks are referred to as a public switched telephone network (PSTN) or plain old telephone service (POTS). Due to bandwidth limitations of plain old telephone service (POTS), there is an inherent inability to efficiently integrate multiple types of media such as telephony, data communication for personal computers (PC), and television (TV) broadcasts. Accordingly, a new broadband architecture is required. This new architecture gives rise to a new array of user services.
Due to the increase in the number of residences having multiple phone lines and the growing popularity of calling features traditionally implemented by private branch exchange (PBX) systems. However, PBX systems are expensive to purchase, operate and have problems interfacing with non-PBX proprietary equipment. Also, operating multiple telephone lines at a residence tends to be costly because of the local telephone company's lack of competition. A need exists for an open architecture residential PBX providing multiple vender equipment to interface with a communication network that can bypass the local telephone company's network, while providing multiple line capabilities to the residences. A need exists for the residential PBX to provide a portfolio of calling features normally associated with high cost and complex PBX systems.
Prior art private branch exchange (PBX) systems are based primarily on a centralized or star network design. All of the telephones and trunk lines converge on a single switching point, such as a programmable switch or a PBX. However, in spite the popularity of this design, there are a number of problems associated with this network architectural design. These problems include:                1. Single point failure—if the switching point fails, the entire telephone network fails.        2. Limited scalability—each switching point is typically usable only within a specific size range. Scaling to a higher level usually means replacing the switch.        3. Closed architecture—the entire switching system from the switching point to the individual telephone handsets is based on a proprietary architecture.        4. Limited support for enterprise networking—networking multiple systems together typically involves the use of expensive leased lines, or voice over net gateway servers, both requiring expensive installation and operating costs.        5. Antiquated administrative tools—programming a PBX system usually requires extensive training of support personnel.        
A need exists for a distributed telephone systems using IP networks to route calls between nodes. Such as system may provide:                1. No central point of failure—this enables users to deploy extremely reliable, fault tolerant telephone networks.        2. Reduced tolls—by routing interoffice calls over a wide area data network toll call costs may be minimized.        3. Unlimited scalability—using switched 100 Mbps or higher speed such as gigabit Ethernet the IP telephone network may be easily scaled and configured.        4. Open architecture—built upon industry standards such as H.323 and Ethernet provide these IP based PBX systems with a high degree of interoperability.        5. Enterprise telephony—a PBX system may be configured across large geographic areas create an enterprise wide system that is affordable for residences.        6. User friendly administrative tools—administering of an IP based PBX system can be simplified minimizing or eliminating programming specific equipment hardware.        